292 Chronicles of Science. [April, 



with its properties before using it as an anaesthetic. He has made 

 several experiments with it himself, and has found that, when 

 respired in a pure condition, protoxide of nitrogen is dangerous ; 

 for, besides loss of sensibility, asphyxia is produced, which may 

 kill the patient ; administered in a state of mixture with oxygen, 

 the only plan which, in M. Hermann's opinion, would not be 

 simply criminal on the part of the operator, it constitutes a very 

 feeble anaesthetic, from which recovery is rapid. Its use has 

 already produced most serious disasters in Germany. 



Tlie Wave-lengths of the Transmission of Muscular and 

 Nervous Action. — In a late Chronicle we noticed Dr. Marey's 

 instrument, the Myograph, with which he has been able to make 

 observations on the muscular susurrus — that is, the separate 

 vibrations which, when succeeding each other sufficiently rapidly, 

 constitute a muscular contraction. Dr. Haughton, of Dublin, has 

 been comparing the rate of these vibrations, and then' lengths, 

 with those caused by nerve action. Wollaston fixed the muscular 

 susurrus, or agitation sufficient to produce contraction, at from 

 20 to 30 per second ; Dr. Collongues, of Paris, at 35 ; and Dr. 

 Haughton, as also Helmhoitz, at 32 in a second. Dr. Haughton, 

 from the so-called tinnitus aurium, which is caused by the action 

 of the nerves, fixes the rate of nerve vibration at 1,024 in a 

 second. From these data it follows that the rate of nerve action 

 is from 29 to 32 times as fast as the rate of muscular action. Dr. 

 Schelske's experiments have shown that the velocity of wave- 

 transmission of sensation in the living body of man is 97 feet per 

 second; and the experiments of Professor Aebe, of Berne, show 

 that the velocity of wave-transmission of muscular contraction in 

 frogs is 3 feet per second. The wave-transmission in nerves is 

 therefore 32 times as fast (or 29 times, if Helmholtz's deter- 

 mination of 88 feet per second be taken) as the wave-transmission 

 in muscles. It appears, from these facts taken together, that the 

 velocity of the wave varies inversely as the rate of vibration when 

 muscles and nerves are compared, and consequently the length 

 of the wave is constant : hence the wave-length of muscular and 

 nervous action, for both lies between 1 ■ 125 and 1 ■ 225 inch. Dr. 

 Haughton considers that important consequences ought to follow 

 from this deduction, if true. Many advantages may flow from 

 identity in wave-length of the muscular and nervous force, and 

 the consequent identity of nodes, notwithstanding the very different 

 velocities with which wave-pulses are propagated along them. 

 The data upon which these calculations are made admit, of course, 

 of great extension. Since, as Dr. Marey has shown, the muscular 

 susurrus in the frog may be only 4 per second, and in some 

 birds 75 per second, it would be as well that all the data should 

 be taken from one animal or class of animals, if the calculation 



